Decks attached directly to houses are common in housing today. Decks are usually elevated above the ground and are supported by an exterior house wall and posts. Often, decks are over ten feet above the ground. Inadequate attachment of the deck to the exterior wall of the house can cause dangerous and even deadly consequences. Even when the deck is initially attached strongly enough to support a given load, incorrect deck attachment practices can lead to premature weakening of the attachment between the house and deck due to water damage and expansion and contraction caused by freezing and thawing in the winter and heat of summer days.
Traditionally, decks have been attached to houses with bolts attaching the deck ledger board to the brick, wood or concrete block wall of the house. The deck ledger is parallel to and should be fastened to the house rim board. However, in the interest of convenience or time savings, sometimes the deck ledger is attached directly to the brick, stone, or siding by screws or lag bolts. This form of attachment is sub-standard, weak, dangerous and against building codes. Brick or stone veneer should never be relied upon to support a load. There is an air gap between brick veneer and wall structure which must be maintained to prevent moisture problems on inner walls. Brick veneer is brittle and susceptible to cracking. Brick veneer is only intended to serve as covering and is no more reliable than aluminum or vinyl siding in terms of load support strength.
Improperly fastening the deck to the building can allow the connection between the house and deck to become weakened. Deck ledger boards are attached by nails to the house sometimes. Heat and cold can cause the ledger board to work away from the house. A large number of people moving around on a deck has a tendency to cause the ledger to pull away from the house and with only nails holding the ledger, the nails can and do slide within their holes. Deck ledger boards should be fastened with lag bolts at least, or better, with bolts and nuts with flat washers to spread the load over the boards. Screws can hold as much as ten times the pull force of similarly sized nails.
The brick is only a siding and should never support much of the load of a deck. Attachment of the deck should be through the house band joist or house foundation wall. The brick isn't attached to the house well enough to prevent a load shift and keep the deck from pulling away from the house altogether. Moreover, when bolting on the ledger they should not be tightened enough to crush the air space behind the brick wall.